This invention relates generally to microelectromechanical structures (MEMS) and particularly to techniques for packaging MEMS.
In some cases, MEMS components such as varactors, switches and resonators need to be packaged in a hermetic environment. For example, particularly with radio frequency MEMS components, there may be a need for hermetic packaging. Such packaging protects the MEMS components from the outside environment.
Conventionally, two approaches have been utilized for hermetic packaging of MEMS components. Ceramic packages with cavities that may be sealed are used in the defense industry. This approach, while reliable, may be cost prohibitive for many commercial applications.
A second approach is to use a glass frit to bond a wafer containing the MEMS components to a cover. However, this technique requires high temperature bonding that may not be suitable for all components utilized in some MEMS applications. In some cases, the glass frit occupies a large area that increases the size of the resulting product and therefore increases its costs. In some cases, the glass frit bonding technology uses wire bonds for electrical connections that may not be adequate in some applications, such as high frequency applications.
Thus, there is a need for better ways to package MEMS components.